Polylactide Stereocomplex

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Schmidt, S.C. and Hillmyer, M.A. (2001) Polylactide stereocomplex crystallites as nucleating agents for isotactic polylactide. Journal of Polymer Science Part B Polymer Physics, 39, 300-313. 

Anderson, K.S. and HiUmyer, M.A. (2006) Melt preparation and nucleation efficiency of polylactide stereocomplex crystallites. Polymer, 47,2030-2035. 

Gallos et al. [6] synthesized stereocomplexed polylactide using reactive extrusion process. The stereocomplexed PLA obtained in a two-step polymerization of L-lactide and D-lactide process to yield poly-L,D-lactic acid multiblocks. In the first step, DSM Micro 15... 

Eukushima, K. and Kimura, Y. (2006) Stereocomplexed polylactides (Neo-PLA) as high-performance bio-based polymers their formation, properties, and application. Polymer International, 55, 626-642. 

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Crystalline structure and molecular dynamics in alpha and alpha crystals of poly(L-lactide) (PLLA) and PLLA/poly(D-lactide) (PDLA) stereocomplex crystals have been investigated by solid-state C CPMAS NMR spectroscopy. The crystal forms of polylactide (PLA) have different line shapes, and resonance splittings in solid-state NMR spectra due to the crystallographically inequivalent sites within crystal unit cell. 

Polylactides (PLAs) have two enantiomeric forms, PLLA and PDLA. It is well known that a 1 1 mixture of PLLA and PDLA can form stable stereocomplex (SC) crystals, which have... 

Ajiro, H., Kuroda, A., Kan, K., Akashi, M., 2015. Stereocomplex film using triblock copolymers of polylactide and poly(ethylene glycol) retain paxlitaxel on substrates by an aqueous inkjet system. Langmuir 31 (38), 10583—10589. 

The most effective technique for obtaiiung exclusive stereocomplexation is to use stereoblock polylactides (sb-PLA) in which both the enantiomeric chains are chemically connected and the chain mixing is allowed to take place at the molecular level. 

The most common strategy to decrease the price or improve the properties of polylactide to fulfill the requirements of different applications is blending. Polylactide has been blended with degradable and inert polymers, natural and synthetic polymers, plasticizers, natural fibers and inorganic fillers. The most common blends include blends with other polyesters such as polycaprolactone or PLA/starch blends. Usually the compatibility between the two components has to be improved by addition of compatibilizers such as polylactide grafted with starch or acrylic acid (114,115). Recently a lot of focus was concentrated on the development of polylactide biocomposites, nanocomposites and stereocomplex materials. In addition various approaches have been evaluated for toughening of polylactide. 

Impressive progress has been made in stereospecific polymerization of cyclic ethers and cyclic esters since the first edition of CPS was published. A novel ROP phenomenon called stereocomplexation, which is especially important when it involves homochiral macromolecules, poly(R)- and poly(S)- polylactides, is analyzed in detail (chapter devoted to cyclic esters). A breakthrough in the stereoregulation of methyloxirane (propylene oxide) polymerization is the subject of a chapter on stereospecific polymerization of oxiranes. 

Shin EJ, Jones AE, Waymouth RM (2012) Stereocomplexation in cyclic and linear polylactide blends. Macromolecules 45 595-598... 

Sterocomplexation between two layers can occur between two stereoregular polymers, as in the case of multilayers obtained with isotactic and syndiotactic PMMA and enantiomeric (l- and D-) polylactides. This type of interaction for LbL assembly has not been extended to many stereoregular materials however, because of the advantages of stmctural regularity observed within stereocomplexed PMMA LbL films, they have found the incorporation of other materials, such as enzjunes and antibodies, within the films important. 

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